← Perplexity Interview Insights
Went with a tree structure which felt like the obvious call.
Start by clarifying requirements and constraints, then design a tree-based data structure with nodes representing files and directories. Implement the core operations (touch, mkdir, ls, rm, rmdir) with careful handling of edge cases like duplicate names, non-empty directories, and path resolution.
Pro tip: Mention that you would use a hash map for children to achieve O(1) lookup, and discuss how to handle concurrent access if the file system needs to be thread-safe. This shows awareness of performance and real-world concerns.
Ask about expected operations, path formats (absolute vs relative), error handling, and whether concurrency or persistence is needed. This ensures you build the right abstraction.
Propose a Node class with attributes like name, isDirectory, children (map), and parent pointer. Explain how this tree structure models the Unix file system hierarchy.
Walk through the implementation of each command: touch (create file), mkdir (create directory), ls (list children), rm (delete file), rmdir (delete empty directory). Highlight path traversal and error cases.
Discuss scenarios like creating a file in a non-existent directory, removing a non-empty directory, duplicate names, and invalid paths. Explain how to return appropriate errors.
Mention potential optimizations (e.g., caching, lazy deletion) and extensions (e.g., permissions, symbolic links, concurrency control) to show depth.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.